Suction drainage systems are often used during surgical procedures to drain body fluids from a patient. Most hospitals use suction drainage systems that employ one or more disposable suction canisters connected to a vacuum source to create a vacuum within the interior of the disposable canister. A flexible suction tube extends from the disposable canister to the source of body fluids in the patient. The vacuum within the canister draws the body fluids through the suction tube into an internal liquid waste receptacle within the canister. These surgical fluids are considered to be biohazardous waste, mostly because of the risk of infection upon exposure.
In many surgical procedures, the volume of body fluids collected in the suction canister exceeds the capacity of a single disposable suction canister. For instance, arthroscopic surgery procedures using saline as a medium generate large volumes of surgical fluids. It is not uncommon to use 20-30 liters of saline during an arthroscopic knee surgery. It is generally accepted that these large volumes of surgical fluids should be regulated and treated as a biohazardous liquid waste.
Usually, it is desirable to collect fluids continuously from the patient without having to interrupt suction when a first suction canister becomes full. To prevent interruptions, two or more suction canisters are typically connected in a serial collection arrangement to accommodate large volumes of surgical fluid. See, for instance, U.S. Pat. No. 4,384,580, entitled "Suction Canister System and Adaptor for Serial Collection of Fluids", by Jan Leviton, assigned to Beckton Dickinson Co., issued on May 24, 1983. Canister racks are used to hold the series of disposable canisters. It is not uncommon to use as many as 20 or even 30 disposable suction canisters during a single surgery.
The handling and disposal of surgical fluids in disposable suction canisters creates a risk of infection to health care workers handling the canisters, especially if the fluids spill or splash. Thus, it is important to keep untreated liquid medical waste isolated, at least until it has been treated properly with a disinfectant (e.g. thorough mixing of liquid medical waste with a chlorine-based disinfectant for an appropriate time period sufficient to rid infectious bacteria and the like). By its nature, liquid medical waste is heavy. Therefore, if the liquid waste is not treated on-site, the cost of shipping the liquid medical waste and disposing the liquid waste at a remote waste treatment center can be financially burdensome. Perhaps due to disposal costs and perhaps due to convenience, there is a tremendous temptation for health care workers to dispose of the untreated liquid medical waste by simply dumping untreated waste into the hospital drain system. Some states and local municipalities restrict this practice, while others do not. Nonetheless, the likelihood of exposure and infection to a health care worker is increased greatly if the health care worker handles and disposes untreated medical waste in this manner.
Several prior art patents disclose techniques designed to facilitate the handling and disposal of biohazardous liquid medical waste. For instance, U.S. Pat. No. 5,185,007 entitled "Suction Drainage and Infection Control System" by Migdow, et al., assigned to Abbott Laboratories, issued on Feb. 9, 1993 and U.S. Pat. No. 5,234,491 entitled "Suction Drainage Infection Control System" to Bryant et al. and assigned to Abbott Laboratories, issued Aug. 10, 1993 describe various techniques for releasing disinfectant into a disposable suction canister to treat the liquid medical waste on-site. One problem with these systems is that the disinfectant is often not thoroughly mixed with the liquid waste. This is especially important when clotted blood is present in the liquid waste because thorough mixing is needed so that the treatment chemical can effectively permeate the blood clots and deactivate infectious organisms.
U.S. Pat. No. 4,900,500 discloses a solidifying agent or gelling compound that is added to the liquid waste after the disposable canister is full, thereby reducing the likelihood of spilling from the disposable canister. After the liquid waste has been solidified, the disposable canister filled with gelled liquid waste is disposed at an incinerator, a landfill or the like. One problem with this technique is that the health care worker must physically open a contaminated canister to add the gelling compound, thus taking the risk of spilling or splashing infectious liquid medical waste as well as exposing the worker to airborne contaminants. To avoid this problem, it is desirable to add disinfectant before solidifying the liquid medical waste in the canister. U.S. Pat. No. 5,092,858 discloses a system designed to solve the problem of inadequate mixing between infectious liquid medical waste and disinfectant due to premature solidification of the liquid medical waste.
The Steris Corporation, Mentor, Ohio (U.S. Pat. No. 5,242,434 entitled "Medical Waste Handling System", by Terry, issued on Sep. 7, 1993) has provided a fluid waste management system that completely replaces the use of disposable suction canisters, and has the ability to treat biohazardous liquid medical waste internally on-site. However, this system has several limitations which compromise its effectiveness. The system contains two concealed, non-disposable canisters having a total capacity of about 40 liters. The canisters are concealed within a metal housing. Liquid disinfectant is put into the concealed canisters before system start-up to disinfect suction drainage fluids collected in the canisters. Surgeons cannot visually monitor the quality of the suction drainage fluid because the canisters are concealed. When the canisters are filled or the surgery is complete, the system must be taken offline for draining and cleaning if it is desired to use the system on another patient.